Explosive-actuated bolt-setting gun

ABSTRACT

An explosive actuated bolt-setting gun includes a housing and a two-part barrel mounted in the housing for axial displacement therein and including front and rear barrel parts, with the front barrel part mounted on the rear barrel part for limited axial displacement against the force of a first spring engaged between the barrel parts. A cartridge chamber is formed in the rear portion of the barrel, and a plate closes the cartridge chamber. A firing pin is operatively associated with the cartridge chamber, and second spring means bias the barrel and the plate forwardly out of firing position except when the barrel is pressed against the target material. The second spring means includes a spring biased plunger engaged with the barrel and a spring engaged with the plate. The initial force of the first spring is at least equal to the terminal force of the second spring means. A protective cap is associated with the front barrel part, and the front barrel part may protrude slightly beyond the work-engaging outer end of the protecting cap.

United States Patent Helmut Oesterle Inventor 3,235,l54 2/1966 Malno 227/10 Feldkirch-Notels, Austria 3,255,942 6/1966 Bell et al 227/8 323 Primary ExaminerGranville Y.Custer, Jr. Y Arr --M 61 d T 45 Patented on. s, 1971 c cw [73] Assignee Hilti Aktiengesellschatt I Schalni Furstemum, Liechtenstem ABSTRACT: An explosive actuated bolt-setting gun includes y y 20,1968 a housing and a two-part barrel mounted in the housing for Germany axial displacement therein and including front and rear barrel P17 03 439-8 parts, with the front barrel part mounted on the rear barrel part for limited axial displacement against the force of a first spring engaged between the barrel parts. A cartridge chamber [54] gf f zf q BOLT SETTING GUN is formed in the rear portion of the barrel, and a plate closes rawmg the cartridge chamber. A firing pin is operatively associated [52] US. Cl 227/8, with the cartridge chamber, and second spring means bias the 227/ barrel and the plate forwardly out of firing position except [51] lnt.Cl 1325c 1/14 when the barrel is pressed against the target material. The [50] Field of Search 227/8, 9, second spring means includes a spring biased plunger engaged 1 l with the barrel and a spring engaged with the plate. The initial force of the first spring is at least equal to the terminal force of [56] References (med the second spring means. A protective cap is associated with UNITED STATES PATEN the front barrel part, and the front barrel part may protrude 2,669,716 2/1954 Catlin 227/8 slightly beyond the work-engaging outer end of the protecting 2,963,707 12/1960 Schulz 227/8 cap.

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l N VIEN 'l ()R H ELM UT OESTERLE EXPLOSIVE-ACTUATED BOLT-SETTING GUN BACKGROUND OF THE INVENTION For safety reasons, bolt-setting guns, if they are designed for higher outputs, preferably are provided with protective caps. The outer ends of these caps constitute stand plates for the bolt-setting gun when the latter is engaged with target material. A problem is presented in that, on one hand, the front part of the barrel is to be flush with the outer end of the protective cap when the gun is pressed against target material, to prevent wobbling of the gun, while, on the other hand, it should be possible also to tire the gun when the front part of the barrel protrudes slightly beyond the outer end of the protective cap, when the gun is pressed against the target material, so that bolts can be set also in uneven target material. For safety reasons, however, firing of the gun should be possible only if a certain angle, usually up to about 7, between the outer end of the protective cap and the target material is not exceeded. The realization of the required flush alignment is rendered very difficult by the longitudinal tolerances for the two-part barrels, and which must be accepted in mass production.

SUMMARY OF THE INVENTION This invention relates to explosive-actuated bolt-setting guns and, more particularly, to an explosive-actuated boltsetting gun in which the initial force of the spring engaged between a front barrel part and a rear barrel part is at least equal to the terminal force of springs maintaining the barrel and a cartridge chamber closure plate out of firing position except when the barrel is engaged with the target material.

The invention is applied to a gun of the mentioned type provided with a known protective cap and in which a spring is engaged between the front and rear parts of the two-part barrel. The initial force of this spring is at least equal to the terminal force of springs maintaining the barrel and a cartridge chamber closure plate out of firing position except when the barrel is engaged with target material.

The invention arrangement assures flush bearing of the front part of the barrel, having the protective cap, on the target material even when the front part and/or the rear part of the barrel are somewhat longer, or somewhat shorter, than the normal length. The limited displaceability of the front part of the barrel on the rear part, in connection with the dimensioning of the strength of the springs, assures that the gun can be fired even when the front part of the barrel projects somewhat beyond the front end of the stand plate when the barrel is pressed against the target material. Due to the design of the spring engaged between the front and rear parts of the barrel, this spring initially will urge the front part of the barrel beyond the protective cap when the bearing pressure is reduced, but only to the extent possible by the limited relative displaceability of the barrel parts. A further reduction of the bearing pressure results in a displacement of the barrel and closure plate from the firing position, so that firing of the gun is no longer possible.

An object of the invention is to provide an improved explosive-actuated bolt-setting gun.

Another object of the invention is to provide an improved explosive-actuated bolt-setting gun including a protective cap and a two-part barrel, in which the two barrel parts are relatively displaceable axially of each other.

A further object of the invention is to provide such a boltsetting gun including a spring engaged between the two barrel parts and spring means biasing the barrel and a closure plate for a cartridge chamber out of firing position except when the barrel is pressed against target material, the initial force of the spring engaged between the two barrel parts being at least equal to the terminal force of the springs biasing the barrel and the closure plate out of firing position.

Another object of the invention is to provide such an explosive-actuated bolt-setting gun in which, even with the presence of the protective'cap, a bolt can be driven in uneven target material.

A further object of the invention is to provide such a gun in which the spring engaged between the frontand rear parts of the barrel initially biases the front barrel part to project beyond the protective cap but, when the bearing pressure is reduced to a certain extent, the barrel and the cartridge chamber closing plate are displaced from the firing position, making firing of the gun impossible.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodirnent thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, a gun embodying the invention includes a rear housing part 1 and a front housing part 2. A grip 3 is rigidly connected with rear housing part 1 by screws 4, as shown more particularly in FIG. 2. Within front housing part 2, there is arranged a housing or sleeve 5 which is fixedly connected with part 2. Parts 2 and 5 are mounted for conjoint axial displacement on a sleeve 6 which is connected, through a journal 7 forming also the fulcrum for opening movement of the front part of the gun, with rear housing part 1.

A rear barrel part 8 is mounted, for axial displacement, in the rear part of sleeve 5, and a front barrel part 9 is mounted for axial displacement in the front portion of rear barrel part 8, the axial displacement being possible only within predetermined limits which are set by the length of an annular slot 10 in which is seated a ring 11. Ring 11 acts as an abutment for one end of the spring 12 whose opposite end engages a shoulder 8a of rear barrel part 8. Spring 12 biases ring 11 against the inner end of front barrel part 9, and thus displacement of barrel 9 in a direction opposite to the bolt-driving direction is possible only against the force of spring 12.

The gun has a protective cap 13 which is disengageably connected with housing part or sleeve 5. A so-called protective cap safety is likewise provided, and consists of a lever 14 having a part 14a which is biased, by a U-shaped spring 16 embracing a bolt 15, into an annular slot 9a of front barrel part 9, if there is no protective cap 13 provided on the gun and the gun is not pressed against the target material. One end of spring 16 is engaged in lever I4, while the other end of the spring bears on a plate 17. Due to the engagement of part of lever 14 in slot 9a, displacement of rear barrel part 8 into firing position by front barrel part 9 is not possible.

A piston 18 is mounted for axial displacement in rear barrel part 8, and has a rear portion of a larger diameter than the remainder of its length. During bolt-driving movement of piston 18, the front portion of this piston is guided in front barrel part 9. In FIG. 1, piston 18 is illustrated in its starting position into which it is brought, in the present case, by means of a rammer. However, other means for returning the piston to the starting position can be used. Preferably, the bolt or nail to be driven by the gun, and which has not been shown, bears, with its rear portion, on the surface of piston 18 leading in the boltdriving direction. In such a case, the movement of the bolt and the piston to the starting position is effected simultaneously.

In the rear portion of barrel part 8, which rear portion has a larger diameter than the remainder of barrel part 8, there is formed a cartridge chamber 19 whose rear end is closed by a closure plate 20 biased into closing position by a spring 21 which is seated in the bottom of a recess in grip 3. Plate 20 has an aperture or bore 204 through which a firing pin 22 can strike against the bottom of the cartridge in chamber 19. The energy for impacting firing pin 22 against the bottom of the cartridge is stored in a spring 23. A spring 24 biases firing pin 22, in the uncooked state, far enough away from the cartridge bottom that firing is not possible.

A pin 26, biased by a spring 25, engages rear barrel part 8 and thus biases the rear barrel part as well as the front barrel part 9 away from the firing position when the gun is not pressed against the target material. The barrel is retained in the starting position by a ball detent 28 retained by a spring 27 and which is then forced into a depression 80 of barrel part 8.

The gun has a trigger 29 which can pivot about a bolt 31 and which is biased into a starting position by a spring 30. When trigger 29 is moved in a direction opposite to the bolt-driving direction, a projection 29a thereon engages a projection 22a of firing pin 22 and moves firing pin 22 in a direction opposite to the bolt-driving direction and against the bias of spring 23. Firing pin 22 thus is cocked. After a certain rearward movement of firing pin 22, projection 29a slides over projection 22a and releases the firing pin which, during its advance, strikes against the cartridge bottom provided the gun is in firing position, thus effecting firing of the cartridge.

For opening the gun, parts 2 and are twisted through 90 and then displaced axially in the bolt-driving direction, after which the gun can be pivoted to the open position about the journal 7.

From the starting position of the gun, indicated by the broken line position of front barrel part 9, springs 21 and 25 are first compressed, when the gun is pressed against the target material, and thus the parts are brought into firing position. lt is only after this, and when the gun is subjected to further pressure against the target material, that spring 12 is compressed, the expansion path of this spring being so limited by the length of annular slot that spring 12 can force front barrel part 9 out of the gun, in the firing position, at the most to a position wherein a maximum angle of about 7 exists between the target material and protective cap 13.

In FIG. 3a the front barrel part 9 is shown in the position when it rides forwardly within the housing to the extent that its shearing ring 9b enters the annual groove 5a. In FIG. 3b the front barrel part 9 is shown displaced rearwardly from the position in FIG. 3a to the point where the rear end of the front barrel part first contacts the ring 11 positioned within the slot 10. in FIG. 1 the front barrel part 9 is shown displacing the ring 11 and the spring 12 to the rearward end of the slot 10.

lclaim:

1. in an explosive-actuated bolt-setting gun including a housing having a front portion and a rear portion, a protective cap mounted on the front portion of said housing, a two-part barrel mounted in said housing for axial displacement therein and including front and rear barrel parts and a first spring means disposed between and arranged to biassaid front and rear barrel parts apart, said front barrel part mounted on said rear barrel part for limited axial displacement thereon against the force of said first spring means positioned between said barrel parts, said front barrel part being coextensive with said protective cap, a cartridge chamber in the rear portion of said rear barrel part, a plate extending transversely of the rear portion of said rear barrel part and forming a closure for said cartridge chamber, said plate having an aperture therethrough opening into said cartridge chamber, a firing pin operatively associated with said cartridge chamber through the aperture in said plate, and second spring means biasing said barrel and said plate out of firing position except when said front barrel part is pressed against the target material and displaces said rear barrel part axially against said second spring means for placing said barrel in the firing position, wherein the improvement comprises that the initial force of said first spring means is at least equal to the terminal force of said second spring means and in the firing position said front barrel part is axially displaceable for a limited extent on said rear barrel part, said protective cap on the front portion of said housing acting as a standplate when the bolt-setting gun is pressed against the target material; and said first spring means comprising an axially extending spring extending about said rear barrel part, a ring positioned on the front end of said spring and arranged to abut against the rear end of said front barrel part, said second barrel part having an axially extending annular slot on the outer periphery thereof in the portion on which said front barrel part is mounted for limited axial displacement, said ring being positionable within the slot in said second barrel part for limiting axial displacement of said front barrel part relative to said rear barrel part without movement of said barrel and said plate out of the firing position by said second spring means so that said front barrel part can be projected forwardly beyond the front end of said protective cap to an extent such that said protective cap can be tilted, relative to the target material to not more than an angle of the order of 7. 

1. In an explosive-actuated bolt-setting gun including a housing having a front portion and a rear portion, a protective cap mounted on the front portion of said housing, a two-part barrel mounted in said housing for axial displacement therein and including front and rear barrel parts and a first spring means disposed between and arranged to bias said front and rear barrel parts apart, said front barrel part mounted on said rear barrel part for limited axial displacement thereon against the force of said first spring means positioned between said barrel parts, said front barrel part being coextensive with said protective cap, a cartridge chamber in the rear portion of said rear barrel part, a plate extending transversely of the rear portion of said rear barrel part and forming a closure for said cartridge chamber, said plate having an aperture therethrough opening into said cartridge chamber, a firing pin operatively associated with said cartridge chamber through the aperture in said plate, and second spring means biasing said barrel and said plate out of firing position except when said front barrel part is pressed against the target material and displaces said rear barrel part axially against said second spring means for placing said barrel in the firing position, wherein the improvement comprises that the initial force of said first spring means is at least equal to the terminal force of said second spring means and in the firing position said front barrel part is axially displaceable for a limited extent on said rear barrel part, said protective cap on the front portion of said housing acting as a standplate when the bolt-setting gun is pressed against the target material; and said first spring means comprising an axially extending spring extending about said rear barrel part, a ring positioned on the front end of said spring and arranged to abut against the rear end of said front barrel part, said second barrel part having an axially extending annular slot on the outer periphery thereof in the portion on which said front barrel part is mounted for limited axial displacement, said ring being positionable within the slot in said second barrel part for limiting axial displacement of said front barrel part relative to said rear barrel part without movement of said barrel and said plate out of the firing position by said second spring means so that said front barrel part can be projected forwardly beyond the front end of said protective cap to an extent such that said protective cap can be tilted, relative to the target material to not more than an angle of the order of 7*. 